In general, a hydraulic excavator as a representative example of a construction machine is constituted by an automotive lower traveling structure, an upper revolving structure which is rotatably mounted on the lower traveling structure, and a working mechanism liftably mounted on a front side of the upper revolving structure, and a ground excavating operation is performed by lifting up and down the working mechanism.
The upper revolving structure is largely constituted by a revolving frame serving as a base frame, a cab located at a left front side of the revolving frame to define an operation room, a counterweight located in a rear end side of the revolving frame for keeping a weight balance with the working mechanism, and a housing cover located in front side of the counterweight to accommodate therein mounted equipments such as an engine, a heat exchanger, and a hydraulic pump. In addition, the housing cover is equipped with an engine cover on the top surface side, which is opened or closed upon performing a maintenance operation of the mounted equipments such as the engine.
Now, upon performing a ground excavating operation or the like with a hydraulic excavator, maintenance operations such as inspections and maintenances are performed in regard to various mounted equipments such as an engine, a heat exchanger, a hydraulic pump and a hydraulic cylinder provided in a working mechanism. Therefore, the hydraulic excavator is usually provided with a tool box for accommodating various tools necessary for a maintenance operation to the mounted equipments (Patent Literature 1: Japanese Patent Laid-Open No. Hei 9-195316A, Patent Literature 2: Japanese Patent Laid-Open No. Hei 11-193548 A).
The hydraulic excavator in the above-mentioned Patent Literature 1 is configured to be provided with a tool locating portion by the use of a space in a hollow side deck provided in the left side of an upper revolving structure and accommodate the tool box in this tool locating portion. Meanwhile, the hydraulic excavator in Patent Literature 2 is configured to use a space formed under a seat stand supporting a driver's seat for providing a tool box on an under side surface of a cover covering a front surface side of this seat stand.
However, the hydraulic excavator in the above-mentioned Patent Literature 1 is configured to accommodate the tool box in the narrow space formed in the side deck, and the hydraulic excavator in Patent Literature 2 is configured to accommodate the tool box in the narrow space formed under the driver's seat. Therefore, in any of the above cases, labors and time are required for taking in and out the tool box at maintenance operating, raising a problem with deterioration of operability at the time of performing inspections and maintenances to the mounted equipments by using a tool.
On the other hand, there is proposed a hydraulic excavator for accommodating a tool box in a housing cover accommodating a mounted equipment such as an engine by mounting the tool box in a counterweight located in a rear end side of an upper revolving structure. In the hydraulic excavator, by opening and closing an engine cover (engine hood) covering an engine, an operation of taking out or in the tool box can be easily performed in a wide space (Patent Literature 3: Japanese Utility Model Laid-Open No. Hei 6-34062 A).